My invention pertains to a station stop and speed regulation system for trains. More specifically, the invention pertains to control apparatus by which regulation of the speed of a rapid transit train can be achieved within preset limits and a station stop program can be initiated and carried to completion to halt the train at a station platform within a predetermined space limit.
The prior art technology in rapid transit train operation used a parallel-series tractive effort control system. In this arrangement, the four propulsion motors and associated control resistors on each car of a train are initially connected in series across the power source. To increase power and therefore speed, the control resistors are cut out in steps and then the motor field energy is weakened. Following this, the motors are switched to a parallel-series combination, normally with parallel pairs of motors connected in series across the power source with the same control resistors. Once again, each resistor is cut out in steps and then the motor fields are weakened, all of this increasing the speed of the train. Obviously, a reverse order of these stepping actions occurs when train speed is being decreased gradually, although the complete shut off of the propulsion motors is always possible. Originally, and still existing in some rapid transit systems, the motorman or train operator manually controls the train speed from a single position in the lead car using switching contactor apparatus. Each car of the train is controlled simultaneously to the same propulsion condition or level through train line wires running the length of the train and automatically connected from car to car when the cars are coupled together to form the train. Subsequently, a variable control of propulsion effort was developed in which variations of the propulsion level exist throughout the train. In other words, the level of propulsion effort on each car is controlled semi-independently of the level existing on other cars of the train, such as, for example, cutting off the propulsion motors of every other car to reduce the total tractive effort. However, an even more sophisticated variable control arrangement is desirable for automatic train operation. For example, it is desirable that each car individually advance to the next higher power state than that called for by the train line control, with this propulsion advance stepped car by car from the leading car to the rear car of the train. The converse of such variable operation applies when the propulsion levels are being decreased to reduce the speed of the train. This car by car stepping of propulsion level requires a separate advance train line control channel as well as an interlock to transfer each step by step cycle completion to the normal propulsion train line apparatus. At the same time, the propulsion train line requires an encoder to convert each advance train line cycle completion signal to a new train line condition. The arrangement must also include interface and/or coordination apparatus to coordinate the variable propulsion control with the train brake control. Automatic train operation also requires a station stopping control arrangement which responds to wayside actuation and interfaces the brake and station stopping with the propulsion controls by incorporating means for sensing and signaling the need for changes. In other words, velocity error detection between the desired and actual speeds of the train is necessary to provide the various interlock interface controls required to coordinate station stopping with the vehicle brake and propulsion control.
Accordingly, an object of my invention is an improved speed regulation system for trains having a variable propulsion control arrangement.
Another object of my invention is a speed regulation system for trains having an improved variable propulsion control arrangement which is coordinated with the braking control apparatus to inhibit the normal braking action while the speed is still being regulated by the propulsion apparatus.
Yet another object of the invention is a station stop and speed regulation system with an improved variable propulsion control arrangement coordinated with the braking control apparatus and station stop control means.
A further object of the invention is a station stop and speed regulation system including an advance train line apparatus and a propulsion train line encoder means to provide preselected stepped changes in the propulsion level of the train.
A yet further object of my invention is a station stop and speed regulation system for rapid transit trains providing coordinated operation between the braking, station stop, and variable propulsion control apparatus.
It is also an object of my invention to provide a propulsion control system for rapid transit trains which varies the tractive effort to either increase or decrease speed in preselected steps through the entire range of propulsion power and coordinates with brake control to inhibit braking effort while the propulsion level remains greater than zero.
Still another object of the invention is a station stop and speed regulation system for rapid transit trains including advance train line control means to step the propulsion level car by car, a propulsion train line control encoder to shift the base propulsion level, and a brake control coordination means to interface between the propulsion effort and braking effort during station stop operations and during normal operation with speed regulation.
A further object of the invention is a propulsion and brake control system for rapid transit trains including advance train line apparatus to increase or decrease the total propulsion of the train in single car steps to the next level, propulsion train line apparatus to periodically shift the base propulsion level from which the advance train line changes are made, and velocity brake error means to detect any difference between actual and desired speeds, drive the advance train line apparatus, and control braking effort to coordinate propulsion and braking applications to eliminate overlap.
A still further object of the invention is a station stop and speed regulation system for rapid transit trains responsive to wayside markers to reduce the train propulsion level in predetermined steps and activate the brake control apparatus to stop the train at a preselected position at the next station.
Other objects, features, and advantages of this invention will become apparent from the following specification and appended claims when taken in connection with the accompanying drawings.